A control unit controls a current flowing through a load that is connected with a switching element by using a pulse width modulation (PWM). In a driving of the load using the PWM, a heat is dissipated due to a switching loss in the switching element. When an abnormal heat dissipation is detected, a fail safe is normally executed to terminate the driving of the load.
However, when the switching element is fully turned off to be in a full off state where a duty ratio is zero in a case where a light load is driven, it is possible that a user becomes uncomfortable due to a sudden lights-out.
According to JP2008-61180A, a load driving control unit executes a control controlling the switching element to be in a fixed full on state, in a case where a temperature abnormal state is detected and the switching element is operating in a normal control. Thus, the heat dissipated due to the switching loss can be suppressed, and the load can be continuously energized.